Contact-free magnetic resonance imaging and spectroscopy with acoustic levitation.

Conventional magnetic resonance measurements often rely on the use of sample containers. This limits the implementation of time-resolved studies at the molecular level of liquid samples undergoing evaporation or other dynamic phenomena that require access to the liquid-gas interface. In this study, we developed a demagnetized acoustic levitator to perform magnetic resonance studies on liquid samples, in a contact-free manner. The performance of the levitator inside a 7.05 T magnetic field was examined and magnetic resonance images of the levitator and the levitated samples were acquired. Then, we collected magnetic resonance spectra of the levitated droplets by applying localized and non-localized pulse sequences and we examined the effect of the droplet shape on the chemical shift. Additionally, we conducted time-resolved experiments on pure solvents and mixtures, and captured physical and chemical molecular interactions, in real-time. This approach enables contact-free studies at the molecular level of dynamic phenomena on a microliter droplet using magnetic resonance techniques.